Vacuum Part Detection

While the bottom camera can detect if a part was successfully picked with reasonable accuracy, you can also use the LumenPnP's vacuum sensors to double check a successful pick. When a part is successfully picked it creates a seal at the end of the nozzle. This seal increases the vacuum pressure in the pneumatic line which is picked up by the vacuum sensors. OpenPnP can use this increase in pressure to detect if a part was successfully picked.

Actuator Setup

Note

The LumenPnP v2 kit machine has different vacuum sensors than the v3 semi-assembled machine. Make sure to follow the steps for your machine version below.

LumenPnP v3

To enable vacuum part detection for v3 machines, we first need to configure the GCode in OpenPnP. This GCode should already be configured correctly in OpenPnP if you're using the default configuration files.

How It Works

The v3 vacuum sensors communicate over I2C. Because they have the same address, we talk to them through an I2C multiplexer. The Gcode commands used to talk to them first tell the multiplexer which device we want to talk to, then we capture a sample of data, then return it back to OpenPnP. The vacuum sensor has three registers holding the sample data, but because OpenPnP only supports raw Gcode commands in these fields, we can only use one byte of data. We capture the most significant bits of the sample as they give us the resolution needed to detect a successful pick. If you'd like to sample the CSB or the LSB byte of data instead, change the second to last command in the commands below to M260 A109 B7 S1 or M260 A109 B8 S1 respectively. Read the datasheet for more information.
Select your GcodeDriver, then under the Gcode tab, select the H1 VAC1 actuator, and select the ACTUATOR_READ_COMMAND setting.

Make sure the following Gcode is present in the field:

M260 A112 B1 S1
M260 A109
M260 B48
M260 B10
M260 S1
M260 A109 B6 S1
M261 A109 B1 S2

With the same H1 VAC1 actuator selected, now choose the ACTUATOR_READ_REGEX setting, and make sure the following is present in the field below:
```
^.*data:(?<Value>.*)
```
Now select the H1 VAC2 actuator, and select the ACTUATOR_READ_COMMAND setting. Make sure the following Gcode is present in the field below:
```
M260 A112 B2 S1
M260 A109
M260 B48
M260 B10
M260 S1
M260 A109 B6 S1
M261 A109 B1 S2
```
With the same H1 VAC2 actuator selected, now choose the ACTUATOR_READ_REGEX setting, and make sure the following is present in the field below:
```
^.*data:(?<Value>.*)
```

LumenPnP v2

v2 Interposers

If you have a v2 machine, please check if you have interposer boards installed.

Select your GcodeDriver, then under the Gcode tab, select the H1 VAC1 actuator, and select the ACTUATOR_READ_COMMAND setting.
Make sure the following Gcode is present in the field:
```
M3426 G2 C1 I1 A110
```
Sensor Address

In the above code snippet, the line M3426 G4 C1 I1 A110 uses A110 to specify which sensor to read from. Due to the way the sensors are programmed by their manufacturer, the address of the sensor can vary. If A110 doesn't work for you, try testing each binary value from 0 to 7 (eg 000, 001, 010 etc) to see which address is correct for your sensors.
With the same H1 VAC1 actuator selected, now choose the ACTUATOR_READ_REGEX setting, and make sure the following is present in the field below:
```
^.*V:(?<Value>\d+).*
```
Select your GcodeDriver, then under the Gcode tab, select the H1 VAC2 actuator, and select the ACTUATOR_READ_COMMAND setting. Make sure the following Gcode is present in the field:
```
M3426 G2 C2 I1 A110
```
With the same H1 VAC2 actuator selected, now choose the ACTUATOR_READ_REGEX setting, and make sure the following is present in the field below:
```
^.*V:(?<Value>\d+).*
```

Enabling and Tuning

With the actuator configured correctly, the next step is enabling part detection for nozzles tips. Select a nozzle tip that you'd like to enable part detection for, and click on the Part Detection tab. You should see a menu similar to the one below:
You might need to tweak the values in the Low Value and High Value fields for both Part On sensing and Part Off sensing. The image shown above has default values for v3 part detection.
Thresholds can be determined by opening the H1:VAC1 or H1:VAC2 actuator window. Click On to turn on your pump and valve, and then click Read. You should see a value appear in the Read Value text box.
Cover the nozzle with your finger tip. Hit Read again. The detection threshold sits in between these two numbers.

Next Steps

Next is the FTP.